Memos Warned Of 747 Fuel Leaks
Federal aviation and Boeing service records contain extensive documentation about where the wing and belly tanks on 747s are susceptible to leaks that can cause fire.
NTSB Vice Chairman Robert Francis, who is heading the investigation into the crash of TWA Flight 800, has declined to compare how much credence investigators are giving to the bomb vs. leaky fuel theories.
But investigators have been piecing together the section of the plane they believe will provide them with the most clues on what caused the belly and right wing tanks to rupture and burn, a sequence that most likely began about a half a minute after things began to go wrong shortly after the plane departed New York’s John F. Kennedy Airport bound for Paris.
The center section, between rows 17 and 28, is where the blast is believed to have originated, a source said. Those seats are near where the central fuel tank is located and where the wings are attached to the plane.
An explosive device precisely placed in the passenger cabin above the belly tank or in a cavity adjoining the belly or wing tank would punch a crippling hole in the airplane’s most vulnerable, volatile area.
Another way things could have gotten started is if fuel or fuel vapors leaking from the belly or wing tanks accidentally ignited in an adjacent cavity.
“It may have been a two-staged event,” said Mike Hynes, an independent crash investigator from Frederick, Okla. “You could’ve had a malfunction of some kind … followed by a big splash of fuel going off.”
Federal aviation and Boeing service records on the 747 show several ways that the wing and belly tanks on 747s are susceptible to leaks that can cause fire.
An extensive account of how a small fire or explosion near the 747’s fuel system during flight can escalate in disaster was detailed in the late 1970s when the safety board concluded a 30-month investigation into the 1976 fire and explosion of an Iranian air force 747-100 near Madrid.
In that case, investigators believe lightning struck a wing, causing a fuel sensor to emit an electrical spark that ignited fuel vapors inside the wing.
An initial flash fire and explosion breached the wing skin above the engine and sent flames licking forward in the slip stream to consume a small section of the wing’s front fiberglass edge.
Once breached, the Madrid jet’s wing skin began peeling back, causing the wing frame to twist and bend. The buckling of the wing caused the outboard engine to begin oscillating wildly from side to side.
The engine snapped off, leaving its fuse pins - fasteners designed to break if the aircraft pitches up or down too drastically - intact.
Officials have declined to say whether they are discussing the possibility of something akin to the Madrid disaster in the TWA 800 crash.